Method and apparatus for configuring power headroom information in mobile communication system supporting carrier aggregation

ABSTRACT

A method and apparatus for configuring Power Headroom Report (PHR) of a User Equipment (UE) efficiently in a mobile communication system supporting carrier aggregation are provided. The method includes generating a header including a LCID for identifying extended PHR and L indicating a length of the extended PHR, and inserting Power Headrooms (PHs) of multiple activated carriers into the extended PHR of one of the carriers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of a prior applicationSer. No. 13/206,779, filed on Aug. 10, 2011, which claimed the benefitunder 35 U.S.C. § 119(e) of a provisional patent application filed onAug. 10, 2010 in the United States Patent Office and assigned Ser. No.61/372,452, of a provisional patent application filed on Aug. 16, 2010in the United States Patent Office and assigned Ser. No. 61/374,160, ofa provisional patent application filed on Sep. 16, 2010 in the UnitedStates Patent Office and assigned Ser. No. 61/383,437, of a provisionalpatent application filed on Oct. 4, 2010 in the United States PatentOffice and assigned Ser. No. 61/389,476, of a provisional patentapplication filed on Oct. 12, 2010 in the United States Patent Officeand assigned Ser. No. 61/392,436, and of a provisional patentapplication filed on Nov. 5, 2010 in the United States Patent Office andassigned Ser. No. 61/410,493, and under 35 U.S.C. § 119(a) of a Koreanpatent application filed on Jul. 26, 2011 in the Korean IntellectualProperty Office and assigned Serial No. 10-2011-0074076, the entiredisclosures of each of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mobile communication systemsupporting carrier aggregation. More specifically, the present inventionrelates to method and apparatus for configuring Power Headroom Report(PHR) of a User Equipment (UE) efficiently in a mobile communicationsystem supporting carrier aggregation.

2. Description of the Related Art

Mobile communication systems developed to provide subscribers with voicecommunication services on the move. With the rapid advance oftechnology, mobile communication systems have evolved to support highspeed data communication services as well as the standard voicecommunication services.

Recently, Long Term Evolution (LTE) is under development as the nextgeneration mobile communication system of the 3^(rd) GenerationPartnership Project (3GPP). The LTE system is a technology for realizinghigh-speed packet-based communication at about 100 Mbps. A discussion isbeing held on several schemes for LTE, including one scheme for reducingthe number of nodes located in a communication path by simplifying aconfiguration of the network, and another scheme for maximallyapproximating wireless protocols to wireless channels.

Unlike voice services, resources for data services are allocatedaccording to the data amount to be transmitted and channel condition.Accordingly, in a wireless communication system such as a cellularcommunication system, a scheduler manages resource allocation accordingto the resource amount, channel condition, and data amount. This is alsothe case in the LTE system, in which the scheduler located in the basestation manages and allocates the radio resource.

Recently, LTE-Advanced (LTE-A) is actively being discussed as anevolution of the LTE with new techniques to increase data rater. Carrieraggregation is one of the representative techniques that are newlyadopted in LTE-A. Unlike the data communication of the related art, inwhich a User Equipment (UE) uses a single uplink carrier and a singledownlink carrier, carrier aggregation enables the UE to use multipleuplink and/or downlink carriers. Since the uplink transmission powerdetermination algorithm is designed for the UE operating with one uplinkcarrier and one downlink carrier, it is difficult to apply thetransmission power determination process for uplink transmission powerdetermination of the UE supporting carrier aggregation. There is a needto define a procedure and method for configuring a Power Headroom Report(PHR) of the UE supporting carrier aggregation.

SUMMARY OF THE INVENTION

Aspects of the present invention are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentinvention is to provide a method and apparatus for configuring a PowerHeadroom Report (PHR) of a User Equipment (UE) efficiently in the mobilecommunication system supporting carrier aggregation. An aspect of thepresent invention is to configure PHR for reporting the Power Headroom(PH) for individual aggregated carriers.

In accordance with an aspect of the present invention, a method forconfiguring a Power Headroom Report (PHR) in a mobile communicationsystem supporting carrier aggregation is provided. The method includesgenerating a header including a Logical Channel IDentifier (LCID) foridentifying an extended PHR and L indicating a length of the extendedPHR, and inserting Power Headrooms (PHs) of multiple activated carriersinto the extended PHR of one of the carriers.

In accordance with another aspect of the present invention, an apparatusfor configuring a PHR in a mobile communication system supportingcarrier aggregation is provided. The apparatus includes a PH calculatorfor calculating PHs of a plurality of activated carriers, and acontroller for generating a header including LCID for identifyingextended PHR and L indicating a length of the extended PHR and forinserting the PHs into the extended PHR of one of the carriers.

In accordance with another aspect of the present invention, a method forreceiving a PHR in a mobile communication system is provided. The methodincludes receiving a header including an LCID for identifying extendedPHR and L indicating a length of the extended PHR, and receiving theextended PHR, and identifying PHs of multiple activated carriersinserted in the extended PHR.

In accordance with another aspect of the present invention, an apparatusfor receiving a PHR in a mobile communication system is provided. Theapparatus includes a transceiver for receiving a header including anLCID for identifying extended PHR and L indicating length of theextended PHR, and for receiving the extended PHR, and a controller foridentifying PHs of multiple activated carriers inserted in the extendedPHR.

In accordance with another aspect of the present invention, method ofgenerating a Power Headroom Report (PHR) in a mobile communicationsystem supporting carrier aggregation is provided. The method includesreceiving a PHR trigger, determining whether to generate an extended PHRbased on the PHR trigger, and when an extended PHR is to be generated,configuring an extended PHR, the extended PHR comprising a headerincluding a Logical Channel IDentifier (LCID) identifying the extendedPHR and a length of the extended PHR, and a payload including PowerHeadrooms (PHs) of multiple activated carriers.

Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainexemplary embodiments of the present invention will be more apparentfrom the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a diagram illustrating an architecture of a mobilecommunication system according to an exemplary embodiment of the presentinvention;

FIG. 2 is a diagram illustrating a protocol stack of a mobilecommunication system according to an exemplary embodiment of the presentinvention;

FIG. 3 is a diagram illustrating an exemplary situation of carrieraggregation in a mobile communication system according to an exemplaryembodiment of the present invention;

FIG. 4 is a conceptual diagram illustrating a principle of carrieraggregation for use in a mobile communication according to an exemplaryembodiment of the present invention;

FIG. 5 is a diagram illustrating a format of a typical Power HeadroomReport (PHR) for use in a mobile communication system according to anexemplary embodiment of the present invention;

FIGS. 6A and 6B are diagrams illustrating a concept of a PHRconfiguration according to an exemplary embodiment of the presentinvention;

FIG. 7 is a diagram illustrating a configuration of a PHR according to afirst exemplary embodiment of the present invention;

FIG. 8 is a flowchart illustrating a method for configuring PHR of aUser Equipment (UE) according to the first exemplary embodiment of thepresent invention;

FIG. 9 is a diagram illustrating a configuration of a PHR according to asecond exemplary embodiment of the present invention;

FIG. 10 is a flowchart illustrating a method for configuring PHR of theUE according to the second exemplary embodiment of the presentinvention; and

FIG. 11 is a block diagram illustrating a configuration of the PHRconfiguration apparatus of the UE according to an exemplary embodimentof the present invention.

Throughout the drawings, it should be noted that like reference numbersare used to depict the same or similar elements, features, andstructures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding, but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the embodiments described hereincan be made without departing from the scope and spirit of theinvention. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but are merely used by theinventor to enable a clear and consistent understanding of theinvention. Accordingly, it should be apparent to those skilled in theart that the following description of exemplary embodiments of thepresent invention is provided for illustration purposes only and not forthe purpose of limiting the invention as defined by the appended claimsand their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

Exemplary embodiments of the present invention relate to a method andapparatus for a User Equipment (UE) to configure a Power Headroom Report(PHR) efficiently in a mobile communication system supporting carrieraggregation. An exemplary mobile communication system to which exemplaryembodiments of the present invention may be applied is described belowwith reference to FIGS. 1 to 3. The description is directed to a LongTerm Evolution (LTE) system, but other wireless communications systemsmay also be employed.

FIG. 1 is a diagram illustrating the architecture of a mobilecommunication system according to an exemplary embodiment of the presentinvention.

Referring to FIG. 1, the radio access network of the mobilecommunication system includes evolved Node Bs (eNBs) 105, 110, 115, and120, a Mobility Management Entity (MME) 125, and a Serving-Gateway(S-GW) 130. The UE 135 connects to an external network via eNBs 105,110, 115, and 120 and the S-GW 130.

The eNBs 105, 110, 115, and 120 correspond to legacy node Bs ofUniversal Mobile Communications System (UMTS). The eNBs 105, 110, 115,and 120 allow the UE establish a radio link and are responsible forcomplicated functions as compared to the legacy node B. In the LTEsystem, all the user traffic including real time services such as Voiceover Internet Protocol (VoIP) are provided through a shared channel andthus there is a need of a device which is located in the eNB to scheduledata based on the state information of the UEs. In order to implementthe data rate of up to 100 Mbps, the LTE system adopts OrthogonalFrequency Division Multiplexing (OFDM) as a radio access technology. TheLTE system adopts Adaptive Modulation and Coding (AMC) to determine themodulation scheme and channel coding rate according to the channelcondition of the UE.

S-GW 130 is an entity to provide data bearers so as to establish andrelease data bearers under the control of the MME 125. MME 125 isresponsible for various control functions and connected to a pluralityof eNBs 105, 110, 115, and 120.

FIG. 2 is a diagram illustrating a protocol stack of a mobilecommunication system according to an exemplary embodiment of the presentinvention.

Referring to FIG. 2, the protocol stack of the LTE system includesPacket Data Convergence Protocol (PDCP) layer 205 and 240, Radio LinkControl (RLC) layer 210 and 235, Medium Access Control (MAC) layer 215and 230, and Physical (PHY) layer 220 and 225. The PDCP layer 205 and240 is responsible for Internet Protocol (IP) headercompression/decompression. The RLC layer 210 and 235 is responsible forsegmenting the PDCP Protocol Data Unit (PDU) into segments in a sizeappropriate for Automatic Repeat Request (ARQ) operation. The MAC layer215 and 230 is responsible for establishing connections to a pluralityof RLC entities so as to multiplex the RLC PDUs into MAC PDUs anddemultiplex the MAC PDUs into RLC PDUs. The PHY layer 220 and 225performs channel coding on the MAC PDU and modulates the MAC PDU intoOFDM symbols to transmit over a radio channel or performs demodulatingand channel-decoding on the received OFDM symbols and delivers thedecoded data to a higher layer. The data input to a protocol entity isreferred to as Service Data Unit (SDU), and the data output by theprotocol entity is referred to as a PDU.

FIG. 3 is a diagram illustrating an exemplary situation of carrieraggregation in a mobile communication system according to an exemplaryembodiment of the present invention.

Referring to FIG. 3, an eNB typically uses multiple carriers transmittedand received in different frequency bands. For example, the eNB 305 maybe configured to use the carrier 315 with center frequency f1 and thecarrier 3210 with center frequency f3. If carrier aggregation is notsupported, the UE 330 transmits/receives data using just one of thecarriers 310 and 315. However, the UE 330 having the carrier aggregationcapability may transmit/receive data using both the carriers 310 and315.

The eNB may increase the amount of the resource to be allocated to theUE having the carrier aggregation capability according to the channelcondition of the UE so as to improve the data rate of the UE. If a cellis configured with one downlink carrier and one uplink carrier, thecarrier aggregation can be understood as if the UE communicates data viamultiple cells. With the use of carrier aggregation, the maximum datarate increases in proportion to the number of aggregated carriers.

In order to mitigate interference, the uplink transmission power may bemaintained below an appropriate level. For this purpose, the UEcalculates the uplink transmission power using a predetermined functionand performs uplink transmission at the calculated uplink transmissionpower. For example, the UE calculates the required uplink transmissionpower value by inputting the input values such as the schedulinginformation including resource amount and Modulation and Coding Scheme(MCS) allocated to the UE and information necessary for estimating thechannel condition such as path loss, and performs uplink transmission byapplying the calculated uplink transmission power value. The availableuplink transmission power value of the UE is limited to the maximumtransmission power value of the UE such that when the calculatedtransmission power value exceeds the maximum transmission power valuethe UE performs the uplink transmission at the maximum transmissionpower. In this case, the uplink transmission power is not enough,resulting in uplink transmission quality degradation. Accordingly, theeNB may perform scheduling such that the required transmission powerdoes not exceed the maximum transmission power. However, since a fewparameters such as path loss is not determined by the eNB, the UEreports its Power Headroom (PH) value to the eNB by means of a PHR.

Several factors influence PH, including 1) allocated transmissionresource amount, 2) MCS to be applied to uplink transmission, 3) PathLoss (PL) of the related downlink carrier, and 4) accumulated value oftransmission power control command. The Path Loss and accumulatedtransmission power control command value are variable according to theuplink carrier such that, when multiple uplink carriers are aggregated,the transmission of PHR may be configured per carrier. However, in orderto transmit the PHR efficiently, it can be advantageous to report thePHs of all the uplink carriers on one uplink carrier. Depending on themanagement policy, it may be necessary to transmit the PH of the carrieron which no Physical Uplink Shared Channel (PUSCH) transmission actuallytakes place. In this case, it may be more efficient to report the PHs ofthe multiple uplink carriers on a single uplink carrier. For thispurpose, the PHR may be extended. The multiple PHs to be contained in aPHR may be arranged in a predetermined order.

FIG. 4 is a conceptual diagram illustrating a principle of carrieraggregation for use in the mobile communication according to anexemplary embodiment of the present invention.

Referring to FIG. 4, 5 uplink carriers may be aggregated for the UE, andone of the aggregated carriers may be selected to transmit the PHs forthe 5 uplink carriers. For example, when three uplink carriers 440, 445,and 450 are aggregated for the UE, a PHR can be configured to carry thePHs for the three uplink carriers.

A PHR is triggered when the path loss of the connected downlink carrieris equal to or greater than a predetermined threshold value, a prohibitPHR time expires, or a predetermined time period elapses after the lastPHR generation. Once PHR has triggered, the UE waits until the timeavailable for the uplink transmission arrives, e.g., the time for whichthe uplink transmission resource is allocated, rather than transmit thePHR immediately. This is because PHR is not time-sensitive information.The UE transmits PHR at the first uplink transmission. PHR is the MAClayer control information and has the length of 8 bits. The first twobits of the PHR are reserved for future use, and the remaining 6 bitsare used to indicate the value in the range between −23 dB and 40 dB asthe available transmit power of the UE.

FIG. 5 is a diagram illustrating the format of a typical PHR for use inthe mobile communication system according to an exemplary embodiment ofthe present invention.

Referring to FIG. 5, a MAC PDU includes a header 505 and a payload 510.The header 505 includes a plurality of sub-headers, and each sub-headercontains information on the data carried in the payload 510, i.e. the ID(LCID) indicating the type of the data.

PHR 520 is also transmitted to the eNB in MAC PDU. In order to transferthe PHR 520, the header 505 includes a sub-header 515 related to the PHR520. The sub-header includes an LCID indicating the PHR 520. PHR 520 hasa fixed value such that the sub-header 515 about the PHR 520 contains nosize information about the PHR 520. Along with the sub-header 515, thepayload 510 includes 1-byte PHR 520. The first two bits of the PHR 520are reserved for future use, and the remaining 6 bits are used toindicate the value in the range between −23 dB and 40 dB. This indicatesthe PH value of the UE.

In the mobile communication system supporting carrier aggregation, ifthe PHs of multiple serving cells are to be reported, the UE aggregatesthe PHs into one PHR. By transmitting the PHs of multiple serving cellsaggregated in one PHR, it is possible to reduce the signaling overheadas compared to the case where the PHs of the multiple carriers aretransmitted separately, and the eNB can acquire the PH for the carriercarrying one PUSCH.

FIGS. 6A and 6B are diagrams illustrating a concept of the PHRconfiguration according to an exemplary embodiment of the presentinvention.

Referring to FIG. 6A, a scenario is shown in which each of two servingcells CC1 and CC2 transmits the PHs of both the serving cells. In thetime duration 605 for which PUSCH transmission occurs in CC1 but not inCC2, the UE can transmit MAC PDU 610 containing the CC1 PH 615 and CC2PH 620. In the time duration 625 for which PUSCH transmission occurs inCC2 but not in CC1, the UE can transmit MAC PDU 630 containing the CC1 H635 and CC2 PH 640. Although no PUSCH is transmitted, the eNB cantrigger PHR to acquire the path loss information on a specific uplinkcarrier.

Referring FIG. 6B, when using four CCs 665, 670, 675, and 680, the UEcan transmit the PHs of the CC2 670, CC3 675, and CC4 680 as well as CC1665. The MAC PDU 660 transmitted in the CC1 665 includes one PHR 655containing all the PHs of the CC1 665, CC2 660, CC3 675, and CC4 680.

Methods for configuring a plurality of PHs efficiently into one PHRaccording to exemplary embodiments of the present invention aredescribed below.

<First Exemplary Embodiment>

In the first embodiment, an extended PHR includes PH information for aplurality of carriers, and the PH information of each carrier isselectively included. Accordingly, the extended PHR varies in sizeaccording to the situation. In the first embodiment, a new PHR format isdefined according to the aforementioned characteristics.

With the introduction of the new extended PHR format in addition to thegeneral PHR format, a new LCID is defined to indicate the extended PHRformat for the discrimination purpose. The newly defined PHR format isreferred to as REL-10 PHR. The extended PHR has a variable length suchthat a value L is added to indicate the length of the extended PHR.

The serving cell of the primary carrier (PCell) may support type 2 PH ornot depending on whether PUSCH and PUCCH are transmitted simultaneously.The PHs of activated Second Cells are included. Since the extended PHRhas a variable length, the sub-header includes a value L indicating thelength of the PHR. Unlike the PCell, the Serving Cell (SCell) of asecondary carrier does not support simultaneous transmission of PUSCHand PUCCH and thus there is no Type 2 PH. The PH information ofindividual carriers is arranged in order of Type 2 PH of PCell→Type 1 PHof PCell→PHs of activated Second Cells in ascending order alongconsecutive bytes. According to exemplary embodiments of the presentinvention, since the Type 2 PH exists in PCell and Type 1 PH is used tointerpret the Type 2 PH, the PH of the PCell is arranged at thebeginning.

Type 2 PH is applied when PUSCH and PUCCH are used simultaneously inuplink. The Type 2 PH of PCell can be defined as follows:PH _(Type 2) =P _(cmax) −P _(PUSCH) −P _(PUCCH)

When only PUSCH is used in uplink, the Type 1 PH of the PCell and SCellis applied and defined as follows:PH _(Type1) =P _(cmax) −P _(PUSCH)

The UE receiving the extended PHR can acquire the information on thepower headroom for PUSCH transmission and PUCCH transmission in thePCell using the Type 2 PH and Type 1 PH of the PCell first and thenprocess the same type PHs, i.e. Type 1 PHs to reduce processing load.

FIG. 7 is a diagram illustrating a configuration of the PHR according toa first exemplary embodiment of the present invention.

Referring to FIG. 7, the MAC header 705 includes the sub-header for theextended PHR. The sub-header 715 includes the LCID indicating inclusionof the extended PHR in the MAC payload 710 and the value L indicatingthe length of the PHR. The extended PHR is composed of the PCell Type 2PH 720, PCell Type 1 PH 725, and SCell PHs 730, 735, 740, and 745 in theMAC payload 710. In the consecutive bytes, the PH information of eachcarrier is arranged in ascending order of Type 2 PH of PCell→Type 1 PHof PCell→PH of 0^(th) SCell→PH of 1^(st) SCell→PH of 3^(rd) SCell.

FIG. 8 is a flowchart illustrating a method for configuring PHR of theUE according to the first exemplary embodiment of the present invention.

Referring to FIG. 8, the UE detects a trigger of PHR in step 805. If thePHR trigger is detected, the UE determines whether the triggered PHR isthe normal PHR or the extended PHR for PHs of multiple carriers in step810. If the triggered PHR is the normal PHR, the UE configures thesub-header and PHR in a normal format in step 815. If the triggered PHRis the extended PHR, the UE configures the sub-header and PHR in aformat according to an exemplary embodiment of the present invention instep 820. After configuring the PHR in corresponding format, the UEencapsulates the sub-header and PHR in a MAC PDU in step 865.

Steps 825 and 830 are a process for configuring the sub-header. The UEsets a newly defined LCID to indicate that the information contained inthe payload is the extended PHR information in step 825. The UE sets thevalue L indicating the length of the extended PHR in step 830. The UEconfigures the PH information in the payload in step 835.

Step 830 may include steps 840 to 860 for arranging the PHs of therespective carriers. If the PUSCH and PUCCH are transmittedsimultaneously, the PCell Type 2 PH should be reported such that the UEinserts the PCell Type 2 PH in the first byte in step 840. The UEinserts the PCell Type 1 PH at the position following the PCell Type 2PH in step 845. The UE inserts the PH of the SCell having the lowestSCell index in step 850. The UE inserts the PH of SCell having the nextlowest SCell index in step 855. Afterward, the UE continues insertingthe PHs of the SCell in ascending order of SCell index in step 860.

<Second Exemplary Embodiment>

In the second embodiment, the PH information for each carrier isselectively required. Accordingly, the extended PHR varies in lengthaccording to the situation. The value L indicating the length of the PHRis defined in the PHR sub-header. It is possible to indicate the SCellin which PH information is transmitted among the activated SecondaryCells by adding a bitmap to the PHR in the payload. This helps transmitPH information more efficiently. The PHR sub-header includes the LCIDnewly introduced to identify the extended PHR.

The extended PHR is variable in length such that the information in thefirst byte on whether the PH information of individual carriers istransmitted enables an estimation of the length. The information isconfigured in the form of a bitmap so as to indicate the PH of PCell orType 2 PH of PCell. Typically, it is assumed that the PH of PCell isalways included and, in this case, there is no need to assign a bit forthis purpose. Whether the PHs of Secondary Cells are included can beindicated in the bitmap. Unlike the Primary Cell, since PUSCH and PUCCHcannot be transmitted simultaneously in the secondary cell, only Type 1PH exists. In the consecutive bytes, the PHs of the carries are arrangedin order of Type 2 PH of PCell→Type 1 PH of PCell→PHs of Secondary Cellsin ascending order or SCell index.

FIG. 9 is a diagram illustrating a configuration of the PHR according toa second exemplary embodiment of the present invention.

Referring to FIG. 9, the MAC header 905 includes the sub-header 915 forthe extended PHR. The sub-header 915 includes the LCID indicatinginclusion of the extended PHR in the MAC payload 910 and the value Lindicating the length of the PHR. The extended PHR is contained in theMAC payload 910 and includes the bitmap 920, PCell Type 2 PH 925, PCellType 1 PH 930, and SCell PHs 935, 940, 945, and 950. Assuming that theextended PHR always includes the PCell Type 1 PH, there is no need toallocate the bitmap separately. Since the PCell Type 2 PH can beincluded according to the situation, a bitmap for indicating the PCellType 2 PH can be necessary but not mandatory. A bitmap is allocated toindicate whether the PHs of individual Secondary Cells exist. If thePCell Type 2 PH and the PHs for all the four activated Secondary Cellsare included, 5 bits are necessary, and all the bits may be set to 1. Inthe consecutive bytes, the PH information of the individual carriers isarranged in ascending order of Type 2 PH of PCell→Type 1 PH of PCell→PHof 0^(th) SCell→PH of 1^(st) SCell→PH of 2^(nd) SCell→PH of 3^(rd)SCell.

FIG. 10 is a flowchart illustrating a method for configuring PHR of theUE according to the second exemplary embodiment of the presentinvention.

Referring to FIG. 10, the UE detect a trigger of PHR in step 1005. Ifthe PHR trigger is detected, the UE determines whether the triggered PHRis the normal PHR or the extended PHR for PHs of multiple carriers instep 1010. If the triggered PHR is the normal PHR, the UE configures thesub-header and PHR in a normal format in step 1015. If the triggered PHRis the extended PHR, the UE configures the sub-header and PHR in aformat proposed according to an exemplary embodiment of the presentinvention in step 1020. After configuring the PHR in correspondingformat, the UE encapsulates the sub-header and PHR in a MAC PDU in step1070.

Steps 1025 and 1030 are the process for configuring the sub-header. TheUE sets a newly defined LCID to indicate that the information containedin the payload is the extended PHR information in step 1025. The UE setsthe value L indicating the length of the extended PHR in step 1030.Steps 1035 and 1045 are the process for configuring the PH informationin the payload. The UE places the bitmap information indicating the SCell in which PH information is transmitted among the activated SCell inthe first byte of the PHR in step 1035. The UE places the PHs in orderaccording to the bitmap information in step 1040.

Step 1040 may include steps 1045 to 1065 for arranging the PHs of therespective carriers. If the PUSCH and PUCCH are transmittedsimultaneously in the uplink such that PCell Type 2 PH exists, the UEinserts the PCell Type 2 PH in the second byte following the first bytecarrying the bitmap in step 1045. The UE inserts the PCell Type 1 PH inthe next byte in step 1050. The UE inserts the PH of the SCell havingthe lowest SCell index in the next byte in step 1055. The UE inserts thePH of the SCell having the second lowest SCell index in the next byte instep 1060. The UE continues inserting the PHs of the Secondary Cells inascending order of the SCell index in step 1065.

According to an exemplary embodiment of the present invention, the UEconfigures the extended PHR in the mobile communication systemsupporting carrier aggregation. The UE generates the MAC headerincluding the PHR type identifier LCID for identifying the extended PHRand the parameter L indicating the length of the extended PHR. The UEarranges the PHs of a plurality of activated carriers into the PHR ofone of the activated carriers. The extended PHR has several consecutivebytes, and the UE arranges the PHs in ascending order of the activatedcarriers in match with the bytes. The UE inserts the Type 1 PHs of thecarriers in the PHR. The UE arranges Type 1 PH of Primary Cell firstamong the activated carriers and then the Type 1 PHs of the SecondaryCells in ascending order of the Scell index. If the PUCCH and PUSCH aretransmitted simultaneously in the uplink, the UE may insert the Type 2PH of the PCell first and then, in series, Type 1 PH of the PCell andType 1 PHs of SCell in ascending order of SCell index. The UE may insertthe bitmap indicating positions of the PHs of activated carriers in theextended PHR in the byte followed by the bytes of the PHs.

FIG. 11 is a block diagram illustrating a configuration of a PHRconfiguration apparatus of a UE according to an exemplary embodiment ofthe present invention.

Referring to FIG. 11, the UE includes a transceiver 1105, a PHcalculator 1115, a controller 1110, a multiplexer/demultiplexer 1120, acontrol message processor 1135, and various higher layer devices 1125and 1130. The UE may also include other units not shown here forclarity, such as a display unit, input unit, or the like. Similarly, twoor more of the above units may be integrated into a single component.While various units may be implemented in software, it would beunderstood that at least some units of the UE would be implemented atleast partially as hardware units in order to carry out their functions.

The transceiver 1105 receives data and control signals in the downlinkcarrier and transmits data and control signals in the uplink carrier. Ifcarrier aggregation is applied, the transceiver may transmit and receivethe data and control signals over multiple aggregated subcarriers.

The PH calculator 1115 calculates the PH and sends the PH to thecontroller 1110 under the control of the controller 1110. If multiplecarriers are aggregated, the PH calculator 1115 may calculate the PHsfor the respective aggregated carriers.

The controller 1110 controls the multiplexer/demultiplexer 1120 togenerate MAC PDUs according to the control signal received via thetransceiver 1105, e.g., the scheduling information indicated in theuplink grant. The controller 1110 may also detect a PHR trigger tocontrol the PH calculator 1115 to calculate the PH when the PHR triggeris detected. The PHR trigger may be determined according to the PHRparameter received from the control message processor 1135. Thecontroller 1110 generates the PHR with the PHs provided by the PHcalculator 1115 and transfers the PHR to the multiplexer/demultiplexer1120. If multiple carriers are aggregated, the controller 1110 maygenerate the extended PHR. The controller 1110 may generate the headerincluding the LCID for identifying the extended PHR and the parameter Lindicating the length of the extended PHR. The controller 1110 may alsoconfigure the PHs of the activated carriers into an extended PHR in oneof the activated carriers. The controller 1110 encapsulates the headerand extended PHR into a MAC PDU.

The multiplexer/demultiplexer 1120 multiplexes the data from the higherlayer devices 1125 and 1130 and/or control message processor 1135 anddemultiplexes the data received by the transceiver 1105 to the higherlayer devices 1125 and 1130 and/or the control message processor 1135.

The control message processor 1135 processes the control messagetransmitted by the network and takes an appropriate action. The controlmessage processor 1135 forwards the PHR parameter carried in the controlmessage to the controller 1110 or the information on the newly activatedcarriers to the transceiver 1105 to set the carriers. The higher layerdevices 1125 and 1130 may be implemented for respective services so asto deliver the data generated by the user service such as FTP and VoIPto the multiplexer/demultiplexer 1120 or process and deliver the datafrom the multiplexer/demultiplexer 1120 to service applications of thehigher layer.

If the user generates the extended PHR as described above, the eNB usesthe extended PHR to determine the uplink transmission power. The eNBincludes a transceiver and a controller. The transceiver can receiveheader including the LCID for identifying the extended PHR and theparameter L indicating the length of the extended PHR and the extendedPHR over one of the multiple aggregated carriers. The controlleridentifies the PHs of the multiple carriers that are contained in theextended PHR. The controller also can determine the uplink transmitpower according to the PHs of individual carriers.

As described above, the PHR configuration method and apparatus for amobile communication system supporting carrier aggregation enablesefficient configuration of the PHR. If multiple carriers are aggregated,the PHR configuration method and apparatus according to exemplaryembodiments of the present invention may configure the PHs of themultiple carriers into a PHR, whereby it is possible to determine theuplink transmission power more efficiently.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method by a terminal in a mobile communicationsystem, the method comprising: generating a MAC PDU including a headerand an extended power headroom report (PHR), the header including asub-header including a logical channel identifier (LCID) for identifyingthe extended PHR and length information on a length of the extended PHR,the extended PHR including information on power headrooms (PHs) ofactivated serving cells; and transmitting the MAC PDU to a base station,wherein, if simultaneous transmission of PUCCH and PUSCH is configured,the extended PHR includes a type II PH and a type I PH of a primaryserving cell of the activated serving cells, and wherein the type I PHis included after the type II PH in the extended PHR.
 2. The method ofclaim 1, wherein the information on the PHs of the activated servingcells is included in ascending order of indices of the activated servingcells.
 3. The method of claim 1, wherein the extended PHR includes abitmap indicating presence of at least one PH for at least one secondaryserving cell.
 4. The method of claim 3, wherein the bitmap is followedby the type II PH of the primary serving cell.
 5. A terminal in a mobilecommunication system, the terminal comprising: a controller configuredto generate a MAC PDU including a header and an extended power headroomreport (PHR), the header including a sub-header including a logicalchannel identifier (LCID) for identifying the extended PHR and lengthinformation on a length of the extended PHR, the extended PHR includinginformation on power headrooms (PHs) of activated serving cells; and atransmitter configured to transmit the MAC PDU to a base station,wherein, if simultaneous transmission of PUCCH and PUSCH is configured,the extended PHR includes a type II PH and a type I PH of a primaryserving cell of the activated serving cells, and wherein the type I PHis included after the type II PH in the extended PHR.
 6. The terminal ofclaim 5, wherein the information on the PHs of the activated servingcells is included in ascending order of indices of the activated servingcells.
 7. The terminal of claim 5, wherein the extended PHR includes abitmap indicating presence of at least one PH for at least one secondaryserving cell.
 8. The terminal of claim 7, wherein the bitmap is followedby the type II PH of the primary serving cell.
 9. A method by a basestation in a mobile communication system, the method comprising:receiving a MAC PDU including a header and an extended power headroomreport (PHR), the header including a sub-header including a logicalchannel identifier (LCID) for identifying the extended PHR and lengthinformation on a length of the extended PHR, the extended PHR includinginformation of power headrooms (PHs) of activated serving cells; andidentifying PHs of the activated serving cells included in the extendedPHR, wherein, if simultaneous transmission of PUCCH and PUSCH isconfigured, the extended PHR includes a type II PH and a type I PH of aprimary serving cell of the activated serving cells, and wherein thetype I PH is included after the type II PH in the extended PHR.
 10. Themethod of claim 9, wherein the information of the PHs of the activatedserving cells is included in ascending order of indices of the activatedserving cells.
 11. The method of claim 9, wherein the extended PHRincludes a bitmap indicating a presence of at least one PH for at leastone secondary serving cell.
 12. The method of claim 11, wherein thebitmap is followed by the type II PH of the primary serving cell.
 13. Abase station in a mobile communication system, the base stationcomprising: a receiver configured to receive a MAC PDU including aheader and an extended power headroom report (PHR), the header includinga sub-header including a logical channel identifier (LCID) foridentifying the extended PHR and length information on a length of theextended PHR, the extended PHR including information of power headrooms(PHs) of activated serving cells; and a controller configured toidentify PHs of the activated serving cells included in the extendedPHR, wherein if simultaneous transmission of PUCCH and PUSCH isconfigured, the extended PHR includes a type II PH and a type I PH of aprimary serving cell of the activated serving cells, and wherein thetype I PH is included after the type II PH in the extended PHR.
 14. Thebase station of claim 13, wherein the information on the PHs of theactivated serving cells is included in ascending order of indices of theactivated serving cells.
 15. The base station of claim 13, wherein theextended PHR includes a bitmap indicating presence of at least one PHfor at least one secondary serving cell.
 16. The base station of claim15, wherein the bitmap is followed by the type II PH of the primaryserving cell.